Search Results (10)

Aquaculture has become a crucial component of global food production, yet catfish (10.8% of global finfish production) breeding programs often lack sufficient genetic data to fully utilize their production potential. In the last 15 years, there have been improvements in this field as two high-density (HD) single nucleotide polymorphism (SNP) arrays (250K and 690K) and low-density panels have been developed for North American channel catfish (Ictalurus punctatus) and blue catfish (Ictalurus furcatus). This lack of genomic tools hinders genetic improvement efforts in other commercially relevant catfish species besides them. Therefore, this review investigated the reason behind the lack of SNP chip usage in genetic-based selections in most catfish breeding programs and the cross-species applicability of the already existing high-density SNP arrays for genotyping members of the Clariidae, African catfish (Clarias gariepinu), and Siluridae, European catfish (Silurus glanis), families. This paper systematically reviews the literature of more than 16 SNP arrays, with 66 non-target species, and assesses the possibility of adapting catfish SNP arrays to the catfish families of interest. With lowered filtering (e.g., MAF > 0) thresholds, the Affymetrix Axiom 250K and Axiom Catfish 690K Genotyping Array could potentially be used on important market species like African and European catfishes. In the long term, chip development would be the solution for these species, but, until then, cross-application is a viable alternative. Despite low polymorphic SNPs (~1%) and call rates (~0%), this SNP array could aid researchers and breeders, improving catfish aquaculture and management. Full article

The hybrid between the female channel catfish (Ictalurus punctatus) and the male blue catfish (I. furcatus) is the best genetic type currently available for commercial catfish farming due to their superior traits. However, further genetic improvements can be achieved by selecting parents with increased combining abilities. Twenty female channel catfish and twelve male blue catfish were crossed in a partial factorial mating design, resulting in forty hybrid families. These families were evaluated for early growth in three different rearing systems, including ponds and aquaria. The early growth performance of hybrid catfish was significantly (p < 0.05) affected by the additive gene action of the female parent and the male parent. There were genotype–environment or genotype–age interactions affecting the combining abilities, both the amount and the type of genetic variation. Dam GCA was significant in all environments/ages; however, sire GCA was variable, and SCA was not significant. These findings suggest that reciprocal recurrent selection for growth could potentially improve the performance of F1 hybrid catfish. Full article

Intelectins (ITLNs) are a family of calcium-dependent lectins with carbohydrate-binding capacity, are distributed across various vertebrates, and play an important role in the innate immune response against pathogen infection. The yellow catfish Pelteobagrus fulvidraco (Siluriformes: Bagridae) is an economically important fish in China. The aim of this study was to quantify the gene expression of ITLN in response to pathogen-associated molecular patterns (PAMPs) stimulation. Here, the ITLN gene of P. fulvidraco was characterized and named PfITLN. The full-length cDNA of PfITLN was 1132 bp, including a 5’-untranslated region (UTR) of 140 bp, a 3’-UTR of 110 bp, and an open reading frame (ORF) of 882 bp encoding a polypeptide of 293 amino acids, which contains a signal peptide and two fibrinogen-related domains (FReDs). PfITLN had a molecular weight of 32.39 kDa with a theoretical pI of 5.03. The deduced PfITLN amino acid sequence had 81%, 64%, and 55% homology with Ictalurus furcatus, Danio rerio, and Homo sapiens, respectively. Moreover, the predicted tertiary protein structure of PfITLN was highly similar to that of other animals, and phylogenetic analysis showed that the PfITLN protein was close to those of other Teleostei. Real-time quantitative reverse transcription-PCR (qRT-PCR) analysis showed PfITLN expression in all examined tissues, with the highest abundance seen in the liver, followed by the head kidney, spleen, trunk kidney, and muscle. After PAMP infection with lipopolysaccharide (LPS) and polyriboinosinic polyribocytidylic acid (poly I:C), the expression levels of PfITLN were significantly upregulated at different time points. These results suggested that PfITLN might be involved in innate immunity. Full article

The catfish processors in the US are required to state the maximum percentage of retained water content (RWC) on the product label. The objectives of our study were to quantify the RWC of processed hybrid catfish fillets from proximate composition and the bacterial load at different processing points. Water content was determined using oven-dry (AOAC950.46,1990) and Near-infrared (NIR) spectroscopy. Protein and fat content were determined by NIR spectrometer. Psychrotrophic (PPC) and Total Coliform (TCC) counts were enumerated using 3MPetrifilm^TM. The fillets’ overall baseline water, protein, and fat content were 77.8, 16.7 and 5.7%, respectively. The RWC of final fresh and frozen fillets were ~1.1=/- 2.0% (not significant) and ~4.5%, respectively, and was not fillet size or harvest season dependent. Baseline water content (78.0 vs. 76.0%) was higher (p ≤ 0.05), and fat content (6.0% vs. 8.0%) was lower (p ≤ 0.05) for small (50–150 g) compared to large fillets (150–450 g). Higher (p ≤ 0.05) baseline PPC (~4.2 vs. ~3.0) and TCC (~3.4 vs. ~1.7) were observed for the warm season (April–July) fillets compared to the cold season (Feb–April). This study provides information to processors and others on estimating retained water and microbiological quality of the hybrid catfish fillets over the process line. Full article

The U.S. catfish industry is seeking production systems that are efficient, intensive, and profitable. Growing foodsize and stocker-sized fish in the same pond is attractive as it is often difficult to obtain larger-sized stockers early each year. This case study evaluated the performance and economics of producing foodsize hybrid catfish and stocker-sized fingerlings in in-pond raceway systems (IPRS) placed into four 0.4 ha ponds. Growout raceways (RW1/RW2) in ponds 1 and 2 were 63 m³, and 45 m³ in ponds 3 and 4 (RW3/RW4). Each pond had one (14 m³) stocker unit raceway and a 5 HP of aeration that maintained adequate dissolved oxygen levels. Average growout production was 12,050 kg/ha in 63 m³ raceways and 12,078 kg/ha in 45 m³ raceways (228 days of production) and achieved harvest weights ranging from 564 to 661 g. The raceway stocker unit had production yields ranging from 3537 to 4388 kg/ha (143 days of production) and achieved harvest weights ranging from 123 to 234 g. Stocker units in ponds 1 and 2 generated 8540 stocker–fingerlings (21,102 fingerlings/ha) and units in ponds 3 and 4 generated 7954 fingerlings (19,654 fingerlings/ha). An investment of USD 39,996 was needed for ponds 1 and 2 and USD 21,196 for ponds 3 and 4. When scenarios were analyzed financially, positive financial net returns occurred when farm level investment decreased, leading to reduced payback periods, increased net present values, and higher internal rates of return. IPRS used stocker units to culture fingerlings for future stocking of foodsize fish. IPRS provided good inventory control, and high production yields compared to traditional pond culture of catfish. Full article

The hybrids of female channel catfish (Ictalurus punctatus) and male blue catfish (I. furcatus) account for >50% of US catfish production due to superior growth, feed conversion, and disease resistance compared to both parental species. However, these hybrids can rarely be naturally spawned. Sperm collection is a lethal procedure, and sperm samples are now cryopreserved for fertilization needs. Previous studies showed that variation in sperm quality causes variable embryo hatch rates, which is the limiting factor in hybrid catfish breeding. Biomarkers as indicators for sperm quality and reproductive success are currently lacking. To address this, we investigated expression changes caused by cryopreservation using transcriptome profiles of fresh and cryopreserved sperm. Sperm quality measurements revealed that cryopreservation significantly increased oxidative stress levels and DNA fragmentation, and reduced sperm kinematic parameters. The present RNA-seq study identified 849 upregulated genes after cryopreservation, including members of all five complexes in the mitochondrial electron transport chain, suggesting a boost in oxidative phosphorylation activities, which often lead to excessive production of reactive oxygen species (ROS) associated with cell death. Interestingly, functional enrichment analyses revealed compensatory changes in gene expression after cryopreservation to offset detrimental effects of ultra-cold storage: MnSOD was induced to control ROS production; chaperones and ubiquitin ligases were upregulated to correct misfolded proteins or direct them to degradation; negative regulators of apoptosis, amide biosynthesis, and cilium-related functions were also enriched. Our study provides insight into underlying molecular mechanisms of sperm cryoinjury and lays a foundation to further explore molecular biomarkers on cryo-survival and gamete quality. Full article

An analysis of instrumental texture differences between channel (Ictalurus punctatus) and hybrid (female channel × male blue, I. furcatus) catfish fillets is presented. Factors including cold-storage type (fresh, frozen, or individually quick frozen (IQF)) and gender were included in the comparisons. Texture was measured at eight positions per fillet by a texture profile analysis (TPA) method that provided seven texture attributes: firmness, toughness, cohesiveness, adhesiveness, chewiness, resilience, and springiness, plus the thickness of the fillets (238 total). All attributes except adhesiveness were found to be statistically different (p < 0.05) between channel and hybrid fillets, with channels having the highest value in each attribute. When cold-storage type was included in the analysis, channels still produced the highest attribute values, but the number of attributes differed with firmness, toughness, and chewiness most associated with the differences in the type of catfish, while the other attributes were affected by cold-storage type. Thickness was found to be a strong covariant to some of the texture attributes, especially toughness, but the determination of difference between channels and hybrids was not affected and TPA profiles provided high levels of differentiation between catfish types. Full article

Adult bigheaded carps Hypophthalmichthys spp. have never been observed in the diets of native fishes in the Mississippi River Basin. In addition, blue catfish Ictalurus furcatus diet preference and foraging behavior have never been studied in the presence of non-native bigheaded carps in the Mississippi River system. We examined the gut contents of adult blue catfish (567–1020 mm, n = 65), captured from a Mississippi River backwater using trammel nets. All items in diets were separated and enumerated, and all fish-like diet items were genetically identified to confirm species-level ID. Bigheaded carp ages were determined by sectioning hard structures (pectoral spines, post-cleithra, and vertebrae). Adult silver carp Hypophthalmichthys molitrix (age 3–5, mean = 3.9 years, SE = 0.2; n = 21) had the highest frequency of occurrence (70%) and constituted the greatest percentage by number (58%) and weight (60%) in/of blue catfish diets. Gizzard shad Dorosoma cepedianum ranked second by all three measures (34%, 25%, and 26%). Finally, 50% to 100% of probable age-based sizes of silver carp exceeded gape measurements of blue catfish, suggesting scavenging was the dominant means of predation. More intensive sampling efforts are required to determine the system-wide importance of bigheaded carp in blue catfish diets. Full article

The hybrid between female channel catfish (Ictalurus punctatus) and male blue catfish (Ictalurus furcatus) is superior in feed conversion, disease resistance, carcass yield, and harvestability compared to both parental species. However, heterosis and heterobeltiosis only occur in pond culture, and channel catfish grow much faster than the other genetic types in small culture units. This environment-dependent heterosis is intriguing, but the underlying genetic mechanisms are not well understood. In this study, phenotypic characterization and transcriptomic analyses were performed in the channel catfish, blue catfish, and their reciprocal F₁s reared in tanks. The results showed that the channel catfish is superior in growth-related morphometrics, presumably due to significantly lower innate immune function, as investigated by reduced lysozyme activity and alternative complement activity. RNA-seq analysis revealed that genes involved in fatty acid metabolism/transport are significantly upregulated in channel catfish compared to blue catfish and hybrids, which also contributes to the growth phenotype. Interestingly, hybrids have a 40–80% elevation in blood glucose than the parental species, which can be explained by a phenomenon called transgressive expression (overexpression/underexpression in F₁s than the parental species). A total of 1140 transgressive genes were identified in F₁ hybrids, indicating that 8.5% of the transcriptome displayed transgressive expression. Transgressive genes upregulated in F₁s are enriched for glycan degradation function, directly related to the increase in blood glucose level. This study is the first to explore molecular mechanisms of environment-dependent heterosis/heterobeltiosis in a vertebrate species and sheds light on the regulation and evolution of heterosis vs. hybrid incompatibility. Full article

Concentrations of As, Cu, Fe, Hg, Pb and Zn and activity concentrations from ^234,238U and ²¹⁰Po in water, fillet, liver and gills were determined in three stocked fish species from the Luis L. Leon reservoir, located in Northern Mexico. The considered species were Lepomis cyanellus, Cyprinus carpio and Ictalurus furcatus. ²³⁸U and ²³⁴U activity concentration (AC) in fillet samples showed values of 0.007–0.014 and 0.01–0.02 Bq∙kg⁻¹ wet weight (ww), respectively. Liver samples for L. cyanellus, C. carpio and I. furcatus present ²¹⁰Po AC of 1.16–3.26, 0.70–1.13 and 0.93–1.37 Bq∙kg⁻¹ ww. Arsenic, mercury and lead concentration intervals in fillet samples were 0.13–0.39, 0.005–0.126 and 0.009–0.08 mg∙kg⁻¹ ww, respectively, while in gill samples they were 0.11–0.43, 0.002–0.039 and 0.02–0.26 mg∙kg⁻¹ ww. The elemental Bioaccumulation Factor (BAF) for fish tissues with respect to their concentrations in water was determined. L. cyanellus showed the highest BAF values for As and total U, being BAF_As = 37 and 40 L∙kg⁻¹ in fillet and gills, respectively, and BAF_{U total} = 1.5 L∙kg⁻¹ in fillet. I. furcatus showed the highest BAF values for Hg and Pb, being BAF_Hg = 40 and 13 L∙kg⁻¹ in fillet and gills, and BAF_Pb = 6.5 and 22 L∙kg⁻¹ in fillet and gills, respectively. Some metal(loid) concentrations are slightly higher than European regulations for fish fillets. The difference in concentrations of metal(loid)s in fillet among the studied species is probably due to their differences in diet and habitat. Full article